What are some examples of using ArrayList in Java?

What are some examples of using ArrayList in Java?

ArrayList in Java is a resizable array implementation of the List interface. Here are a few examples:

1. Creating an ArrayList:

   ArrayList<String> list = new ArrayList<>();
   

2. Adding elements:

   list.add("Apple");
   list.add("Banana");
   

3. Accessing elements:

   String fruit = list.get(0); // Returns "Apple"
   

4. Iterating through the list:

   for (String item : list) {
       System.out.println(item);
   }
   

5. Removing elements:

   list.remove("Banana");
   

Would you like to see more examples or specific use cases?

Can you explain how to sort an ArrayList?

Certainly! You can sort an ArrayList using the Collections.sort() method. Here's an example:

ArrayList<Integer> numbers = new ArrayList<>();
numbers.add(5);
numbers.add(2);
numbers.add(8);

Collections.sort(numbers);

After sorting, the numbers list will be in ascending order. You can also sort a list of custom objects by implementing the Comparable interface or using a Comparator. Would you like to see an example of that?

Yes, please show me how to sort custom objects.

To sort custom objects, you can implement the Comparable interface in your class. Here's an example:

class Person implements Comparable<Person> {
    String name;
    int age;

    Person(String name, int age) {
        this.name = name;
        this.age = age;
    }

    @Override
    public int compareTo(Person other) {
        return this.age - other.age; // Sort by age
    }
}

ArrayList<Person> people = new ArrayList<>();
people.add(new Person("Alice", 30));
people.add(new Person("Bob", 25));

Collections.sort(people);

This will sort the people list by age. You can also use a Comparator for more complex sorting. Would you like to know more about that?